WIN CASH PRIZE: IF YOU KNOW IT CONTEST-question no. (1)

here the first question out of five,plz join the site & then comment your answer to win.

The internal energy of a body means :

(a) Sum total of its kinetic and potential energy of its constituent molecules. 

(b) its kinetic energy 

(c) Total kinetic energy of its constituent molecules 

(d) Sum total of its kinetic and potential energy